Pharmacokinetic Study of Intravenous Lidocaine in Young and Elderly Patients

Information and presentation of the proposed study to participants during the anesthesia consultation scheduled prior to surgery, including provision of the information document and consent form. Trial participants will have at least 2 days to decide whether or not to take part in the trial.

"Participants will be welcomed according to the usual process in the digestive, hepatic, urological, or gynecological surgery service. The inclusion visit will coincide with the pre-anesthesia visit during which the absence of contraindications for starting the study will be verified, particularly the occurrence of any health changes since the anesthesia visit that would contraindicate anesthesia or lidocaine administration. During this visit, participant consent will be obtained. The informed consent form must be signed no later than the morning of the intervention.~For women of childbearing age, the absence of current pregnancy will be verified orally for each participant included. A pregnancy test may be performed if the participant so wishes, but a systematic test is not justified."

Induction of anesthesia will be at the discretion of the attending anesthesiologist, with a lidocaine bolus of 2 mg/kg administered over 1 minute, followed by a continuous IV infusion of 2 mg/kg/h.

Blood samples of 3 mL will be collected in heparinized tubes without gel of 4 ml at 30, 60 and 120 minutes after the start of lidocaine infusion, then every two hours during surgery, and two finals samples at 15 and 60 minutes after the infusion stops.

. Maximal pain reported in the post-anesthesia care unit (PACU) and maximal pain at rest and with movement at 24 hours post-extubation will be recorded.

Any adverse effects/events will be documented from the start of lidocaine administration until 24 hours post-extubation,

A biological blood test, not performed in routine practice, will be carried out to measure the following parameters: albumin, ASAT, ALAT, PAL, GammaGT, total and conjugated bilirubin, creatinine, with calculation of GFR.